We thank The Japan Society of Vacuum and Surface Science to organize this special issue for young researchers in Vacuum and Surface Science. The activities of the division of young researchers in the society originally started in 2010. We have organized seminars in which we invite approximately 5 lectures to learn both the basic and the cutting-edge part of topics as well as promote interactions between the participants. In addition to the activities, we would be glad if we could contribute to the society introducing young researchers and telling our opinions to all members of the society via the special issue.

We demonstrate a novel method to manipulate the Fermi level around the Van Hove singularity (VHS) in Li-intercalated graphene on the SiC single crystal. By angle-resolved photoemission spectroscopy, we observed a Lifshitz transition around the VHS when the thickness of graphene exceeds four layers. We calculated the band structure of a multilayer system with different stacking sequences of graphene and Li layer. The so-called stage 2 model reproduces the Lifshitz transition, where Li occupies every other interlayer of graphene. These properties allow us to explore the electronic phase diagram around the VHS by tuning the thickness.

An electrochemical bias-applied setup for operando hard X-ray photoelectron spectroscopy was developed to investigate bulk-sensitive and element-selective electronic structures of all-solid-state batteries. A model thin film cell was prepared by depositing a LiCoO₂ positive electrode (35 nm) and an Al current collector (10 nm) on the solid electrolyte substrate. A negative Li metal electrode was deposited with a Li₃PO₄ buffer layer on the back side of the substrate. The changes of the core levels and the valence bands were successfully observed at the specific voltage during the charge–discharge process. The reversible changes in the Co 2p_3/2 and O 1s spectra suggested that both of Co cations and O anions contributed to the redox mechanism of LiCoO₂.

Nonevaporable getter (NEG) pumps are widely used in ultra-high vacuum (UHV) apparatus to evacuate residual gasses efficiently in UHV of 10–7 Pa or less. NEG pumps can be use in oil-free, noise-free, vibration-free, space-saving, energy-saving and low-cost. We have developed a new type of NEG pump, named oxygen-free Pd/Ti. A pumping speed of the Oxygen-free Pd/Ti did not decrease after repeated cycles of pumping, baking and air vent. The pumping speed of H2 and CO at room temperature were easily restored by baking at 406 K (133℃) for 12 hours. In this study, we have investigated the dependence of pumping performance and peeling resistance of ICF152 formed bellows with oxygen-free Pd/Ti deposited on stainless steel with surface finishing of 2B or Bright Anneal. We also conducted a test to confirm that peeling did not occur when the bellows was stretched and retracted.

We introduce the results of in situ observation of the surface and the solid-liquid interface of calcium carbonate in atomic-level by frequency modulation atomic force microscopy (FM-AFM) in the presence of additives. We have found that the calcite surface transformed into the aragonite structure by the cooperative effect of magnesium and a hydrophilic polypeptide. Furthermore, high-resolution imaging of solid-liquid interface revealed that these additives did not adsorb on the calcite surface but significantly changed the hydration structure in the vicinity of the surface. Especially magnesium ions contribute to change the hydration structure due to their hydrophilicity.

We investigated the oxidation of oxygen vacancies at the surface of anatase TiO₂(001) using a supersonic seeded molecular beam (SSMB) of oxygen. The oxygen vacancies at the top surface and subsurface could be eliminated by the supply of oxygen using an SSMB. Oxygen vacancies are present on the surface of anatase TiO₂(001) which is not performed surface cleaning prior to XPS measurements under ultra-high vacuum. These vacancies, which are stable in the ambient condition, could also be effectively eliminated by using the oxygen SSMB.